A Florida college student studying marine biology said she's "ready to take a break from the beach for a while" after being swept to sea for 16 hours off the coast of Honduras.

Heather Barnes, 20, a third-year student studying marine biology at the New College of Florida, went snorkeling alone before dawn on Friday to collect coral samples.

"I started cramping in my stomach and leg, and get pushed out by the currents way out," Barnes wrote on her Facebook page. "I try to stay in the same spot thinking people will search for me soon, but after two hours I still didn't see anyone."

When Barnes didn't show up for breakfast at 7:30 a.m. that morning, her professor supervising the trip, Sandra Gilchrist, said she knew something was wrong.

"I was furious with her when we realized she had gone out with herself. She knows better," Gilchrist said. "The search was immediately on."

Rescue boats were deployed at 7:50 a.m., Gilchrist said, adding that local fisherman were alerted to keep an eye out for Barnes, who had gone into the water with just a snorkeling mask and a wetsuit.

The rescue effort expanded to include 100 people by midday, Gilchrist said. However, a shoreline search showed no signs of Barnes, leading her professor and fellow students to fear the worst.

"The wind was blowing to the point where there were swells so strong, we wouldn't have been able to have seen her even if we were 30 feet away, unless we were on a crest," Gilchrist said.

Meanwhile, after treading water in place for a couple of hours, Barnes wrote that she still didn't see anyone.

"I realize if I'm going to make it I have to swim back myself," she wrote.

Aided by the buoyancy of her wetsuit and the changing direction of the wind, Barnes began swimming toward a light she saw on shore and focused on going toward it, even as night fell, Gilchrist said.

After hours of swimming, Gilchrist said Barnes pulled herself over a coral reef and arrived on shore, where locals gave her water before putting her in a kayak and taking her back to the area where she was staying.

"My first reaction was I thought they were bringing back her body, because it was so long and it was dark. Then, one of my students came out and said, 'She's alive! She's alive!'" Gilchrist said. "Everyone broke out in tears and grabbed her."

Aside from exhaustion, Barnes suffered sunburn and jellyfish stings, and is now back in Florida recuperating from her ordeal.

Gilchrist said students were given an extensive safety lecture before the annual summer trip, but next year she plans to institute an additional safety measure -- requiring each student to tether a bright orange life jacket to his or her body, even if they're snorkeling. She said she's also considering using GPS devices to track students in the water.